xpath multiple tag select

Question

For the given XML how can I select c,d,g,h (which will be child tags of b not in j) using xpath?

XML

<a>
 <b>
  <c>select me</c>
  <d>select me</d>
  <e>do not select me</e>
  <f>
    <g>select me</g>
    <h>select me</h>
  </f>
 </b>

 <j>
  <c>select me</c>
  <d>select me</d>
  <e>do not select me</e>
  <f>
    <g>select me</g>
    <h>select me</h>
  </f>
 </j>
</a>

I thought of using following to grab the result but it doesn't give me g,h values

xpath.compile("//a/b/*[self::c or self::d or self::f/text()");

java code I used

import org.w3c.dom.*;
import javax.xml.xpath.*;
import javax.xml.parsers.*;
import java.io.IOException;
import org.xml.sax.SAXException;

 public class XPathDemo {

   public static void main(String[] args) 
   throws ParserConfigurationException,SAXException,IOException,PathExpressionException {

   DocumentBuilderFactory domFactory = 
   DocumentBuilderFactory.newInstance();
   domFactory.setNamespaceAware(true); 
   DocumentBuilder builder = domFactory.newDocumentBuilder();
   Document doc = builder.parse("test.xml");
   XPath xpath = XPathFactory.newInstance().newXPath();

   XPathExpression expr = xpath.compile("//a/b/*[self::c or self::d or self::f]/text()");

  Object result = expr.evaluate(doc, XPathConstants.NODESET);
  NodeList nodes = (NodeList) result;
    for (int i = 0; i < nodes.getLength(); i++) {
        System.out.println(nodes.item(i).getNodeValue()); 
   }
}

}

Can anyone help me with this?

Thanks a lot!!!

Solution 1

Use:

 //a/b/*[not(self::e or self::f)]
|
 //a/b/*/*[self::g or self::h]

In case you know the structure of the XML document well and it is true that the only grand-children that //a/b can have are g and/or h, then this can be simplified to:

 //a/b/*[not(self::e or self::f)]
|
 //a/b/*/*

In XPath 2.0 this can be written even simpler as:

 //a/b/(*[not(self::e or self::f)] | */*)

Solution 2

Use this xpath if you want to select all c, d, g, h nodes:

"//c|//d|//g|//h"

Use this, if you want to specify the full path from the root:

"/a/b/c|/a/b/d|/a/b/f/g|/a/b/f/h"

Or if you want all c, d, g or h, which are within b:

"//b//c|//b//d|//b//g|//b//h"

Also, in your code: use nodes.item(i).getTextContent() instead of GetNodeValue.

Solution 3

how can I select c,d,g,h (which will be child tags of b not in j) using xpath?

XPath 2.0

"/a/b//*[matches(name(),'^c$|^d$|^g$|^h$')]"

To stay with your initial location path, XPath 1.0 should be:

"/a/b//*[name()='c' 
  or name()='d' 
  or name()='g' 
  or name()='h']"

Or, following your usage of axis:

 "/a/b//*[self::c 
  or self::d 
  or self::g 
  or self::h]"

By appending to the location paths above text(), you will get the text node from each related tag.

PS: The solution given by @fiver sould be changed to /a/b/c|/a/b/d|/a/b/f/g|/a/b/f/h.

Comments

[Pavithra Gunasekara]

Hi ,thanks for your help, I edited question I need only the tags inside b... I tried using your query but something is wrong, it doesn't give any result ...

[Petar Ivanov]

im not java expert - what is this class that you are using - can you post a code that compiles?

[Emiliano Poggi]

"Note that you shouldn't include a in the xpath, because a is the root." is this assertion a java-related one? Because in XPath it's totally wrong. The root is /.

[Petar Ivanov]

Hm, I thought so too in fact. I am not java expert, I tested this in C# and when I had /a it didn't work - so I assumed it's because it's root...

[Emiliano Poggi]

No, that's probably related to the object you are using in C# which starts from a. So you are inferring bad.

[Pavithra Gunasekara]

Thanks a lot for your help... I used this and solved my problem XPathExpression expr = xpath.compile("//b/c | //b/d | //b/f/g |//b/f/h/text()");

[Pavithra Gunasekara]

Thanks a lot Dimitre this way is much simpler... :)

[Emiliano Poggi]

Here's finally where my rep. 15 is gone :P! +1 anyway you are true.

[Emiliano Poggi]

@Paithra: do not worry! That's the rep ;-)